Method for improving the resonances of stringed instruments

ABSTRACT

A process whereby a stringed instrument may be altered after assembly so as to achieve maximum efficiency and tonal quality. Sandpaper, manipulated through the end pin hole of an assembled instrument is used to change the prime wood tones and phase differentials of the resonant cavity to optimum levels.

United States Patent [191 [111 3,884,109 Johnson May 20, 1975 METHOD FORIMPROVING THE RESONANCES OF STRINGED INSTRUMENTS Inventor: Charles s.Johnson, 5208 s. 12th St., Arlington, Va. 22204 Filed: Apr. 26, 1974Appl. N0.: 464,346

References Cited UNITED STATES PATENTS 4/1963 Westlake 84/275 3,136,1966/1964 Charlesworth 84/275 Primary ExaminerJoseph W. Hartary AssistantExaminer-John F. Gonzales Attorney, Agent, or Firm-Larson, Taylor andHinds 5 7] ABSTRACT A process whereby a stringed instrument may bealtered after assembly so as to achieve maximum efficiency and tonalquality. Sandpaper, manipulated through the end pin hole of an assembledinstrument is used to change the prime wood tones and phasedifferentials of the resonant cavity to optimum levels.

5 Claims, No Drawings METHOD FOR IMPROVING THE RESONANCES OF STRINGEDINSTRUMENTS FIELD OF THE INVENTION This invention relates to themanufacture of stringed instruments, and, more particularly, internallyaltering an assembled instrument so as to achieve maximum efficiency andtonal quality.

BACKGROUND OF THE INVENTION It is well known in the art that the topsand backs of violins must be constructed to sound more than a semitone,yet less than a full tone apart for maximum resonance. When they areexactly equal or more than a full tone apart, a poor instrument results.In addition, the frequency peaks of top and back should alternate. Thetonal requirements of a stringed instrument are explained in an articleentitled The Physics of Violins, by Carleen Hutchins in ScientificAmerica, Nov. 1962, page 79. v

All of the required work to achieve optional tonal quality is done priorto assembly of the top and back, and, discounts the effect of varnish,which is unequally applied due to the different densities of woodemployed, usually, maple and spruce. Instrument makers have for hundredsof years been preoccupied by the individual sound of the top and back ofan instrument, and the mystery of a secret varnish, and have had toassume that the whole, when finished is to equal the sum of its parts.Individually these parts are most vibrant at their outer edges, however,when glued together the situation is reversed and it is the center areaof the instrument that is most vibrant. Thus, once assembly of theindividually designed parts was accomplished, nothing could be done tosignificantly improve the instruments tonal qualities. Air resonancescould be altered by changing the size of an instrumentsfhole, but, asdescribed in the aforementioned article, such a large increase in thesize of an f hole would be required to alter the air resonance by arelatively small amount, that this process alone is impractical.

SUMMARY OF THE INVENTION According to the invention, a process isprovided whereby the prime wood resonance of an intrument is altered,after assembly, to achieve maximum efficiency and tonal quality.

The inside of the back of an assembled violin is sanded by a stiff wireinserted through the pin hole at the base of the instrument. In order toutilize the pin hole for this process, the tail piece loop, usuallyfastened to a button in the pin hole, must be externally clamped, so asto permit tuning the instruments strings to concert pitch. By carefullysanding the back of the instrument, the prime wood tone of theinstrument and the air resonance tone are brought into consonance,preferably a muscial fifth apart. In a similar manner, the bass bar issanded to achieve proper phasing of the resonance tones.

DESCRIPTION OF THE PREFERRED EMBODIMENT As described in the abovementioned article, the cations of the two chief resonant tones, theprime wood tone and the air tone, are essential to the production ofhigh quality instruments. These tones are detectable by sliding onesfinger down the string. An individual with a musically trained ear candetect the sound level peaks at these two locations, but a sound levelmeter, commonly referred to as a VU meter, allows even the untrained earto detect thesetwo. sound peaks. While the present invention isapplicable to all stringed resonant body instruments, a preferredembodiment is described in relation to a violin, since the parts thereofare well known to those skilled in the art.

The prime wood tone and the air tone are reflected in every note that isplayed on an instrument. The objective of the present process is tobring these two tones in consonance to create a perfect chord. Forexample, the two tones could be set a musical fourth, fifth or sixthapart, each resulting in a different quality chord. According to thepreferred embodiment, the musical fifth is selected. Ideally, this fifthinterval should correspond to the middle two strings of a violin, A andD, but any chord may be selected. As mentioned in the above article, theresonant peaks of a good Stradivarius instrument have been located atapproximately G sharp and C sharp, relatively close to A and D, whileinferior instruments have their resonant peaks a muscial seventh or moreapart.

In order to'adjust these two resonance peaks, the instrument must befully assembled, strung, and tuned to concert pitch. Since a feature ofthe present process involves working through the end pin hole of theinstrument, the button, around which the tail piece end loop is usuallyfastened, is removed. The tail piece must be temporarily fastened toallow concert tuning of the instrument. This fastening can be achievedby securing a nylon ribbon or other strong material to the tail pieceend loop, bringing the ribbon around the end of the instrument, up theback of the instrument and fastening it to the back of the fingerboard,thus straddling the pin hole.

In an alternative embodiment, a clamp, similar to the clamp of a chinrest assembly is fastened to the end of an instrument with the tailpiece end loop secured to it.

According to the invention, the air resonance tone is located first andbrought as close as possible to D by increasing the size and shape ofthe instruments f holes. The technique of changing air resonance bychanging the size of the f holes is known in the art.

The prime wood tone is then brought into consonance by sanding theinside of the instruments back piece. A small piece of sand paper, aboutthe size of a quarter, is dropped into the air chamber through an fhole. The sandpaper may be reinforced with a thin metal backing. A pieceof stiff wire, for example, coat hanger wire, bent and sharpened at oneend is inserted through the end pin hole, and used to manipulate thesandpaper. By repeating the steps of gently sanding the inside of theback of the instrument and testing the location of the prime wood tone,the latter can slowly be brought into consonance, at the desiredinterval (i.e., a fifth) with the air resonance tone.

While the proper interval between resonance peaks is important, optionalperformance is achieved when these tones are in phase, since out ofphase vibrations will tend to conceal each other. In a manner similar tothat described hereinabove, the bass bar is gently sanded by a piece ofsandpaper manipulated through the end pin hole by a stiff wire. Thisadjustment is very critical and the correct in-phase point can bemissed. A VU meter can aid to the location of that point as the soundlevel of the instrument, when the resonant tones are in-phase, isdramatically higher than when out of phase. If the in-phase point ismissed, additional sanding of the bass bar will eventually bring thein-phase point back again. The necessity for proper phasing isillustrated by the very existence of a bass bar, which was originallydesigned to ensure proper phasing of various parts of the instrument andnot for support.

Thus, the prime wood tone and air resonance tones can bebrought intoconsonance and in phase after the violin is fully assembled.

The temporary fastening means is then removed, the button inserted inthe end pin hole and the tail piece end loop placed around it, therebypermitting final stringing.

Although the invention has been described with respect to an exemplaryembodiment thereof, it will be understood that variations andmodifications can be effected in these embodiments without departingfrom the scope and spirit of the present invention.

I claim:

1. A processfor improving the resonances of stringed instruments afterassembly thereof comprising the steps temporarily securing the tailpiece of said instrument by external means so as to permit saidinstrument to be strung and concert tuned without the use of the end pinhole of said instrument;

adjusting the air resonance tone of said instrument to a desired pitchby changing the size and shape of the f-holes of said instrument;

adjusting the prime wood tone of said instrument to a desired musicalinterval from said air resonance tone by the steps of: inserting a pieceof sandpaper into the air chamber ofsaid instrument through an f holethereof; introducing a piece of stiff wire through said end pin holeinto said air chamber to permit manipulation of said sandpaper by saidstiff wire; and alternately sanding the inside of the back of saidinstrument and testing said prime wood tone location, until said primewood tone reaches the desired pitch;

and, bringing said prime wood tone and said air resonance tone intophase by sanding the bass bar of said instrument with said piece ofsandpaper manipulated by said piece of stiff wire inserted into said airchamber through said end pin hole.

2. A process as claimed in claim 1 wherein said air resonance tone, saidprime wood tone and said inphase point are located by means of a soundlevel meter (VU meter).

3. A process as claimed in claim 1 wherein the step of temporarilyfastening said tail piece uses a piece of nylon ribbon secured to thetail piece end loop of said tail piece, said ribbon positioned along theback of said instrument and fastened to th e fingerboard thereof,thereby permitting access to said end pin hole.

4. A process as claimed in claim 1 wherein said interval between saidair resonance tone and said prime wood tone is a musical fifth.

5. A process as claimed in claim 1 wherein said instrument is a violin,said air resonance tone is a D (293 H and said prime wood tone is an A(440 H

1. A process for improving the resonances of stringed instruments afterassembly thereof comprising the steps of: temporarily securing the tailpiece of said instrument by external means so as to permit saidinstrument to be strung and concert tuned without the use of the end pinhole of said instrument; adjusting the air resonance tone of saidinstrument to a desired pitch by changing the size and shape of thef-holes of said instrument; adjusting the prime wood tone of saidinstrument to a desired musical interval from said air resonance tone bythe steps of: inserting a piece of sandpaper into the air chamber ofsaid instrument through an f hole thereof; introducing a piece of stiffwire through said end pin hole into said air chamber to permitmanipulation of said sandpaper by said stiff wire; and alternatelysanding the inside of the back of said instrument and testing said primewood tone location, until said prime wood tone reaches the desiredpitch; and, bringing said prime wood tone and said air resonance toneinto phase by sanding the bass bar of said instrument with said piece ofsandpaper manipulated by said piece of stiff wire inserted into said airchamber through said end pin hole.
 2. A process as claimed in claim 1wherein said air resonance tone, said prime wood tone and said in-phasepoint are located by means of a sound level meter (VU meter).
 3. Aprocess as claimed in claim 1 wherein the step of temporarily fasteningsaid tail piece uses a piece of nylon ribbon secured to the tail pieceend loop of said tail piece, said ribbon positioned along the back ofsaid instrument and fastened to the fingerboard thereof, therebypermitting access to said end pin hole.
 4. A process as claimed in claim1 wherein said interval between said air resonance tone and said primewood tone is a musical fifth.
 5. A process as claimed in claim 1 whereinsaid instrument is a violin, said air resonance tone is a D (293 Hz) andsaid prime wood tone is an A (440 Hz).